Project Summary and Relevance (30 lines of text) Project Summary: The goal of this application is to purchase a 9.4T/20 cm bore horizontal MR magnet as a replacement and upgrade for a 4.7T/40 cm magnet which was used as a shared resource for 13 years at MSKCC for in vivo biomedical applications, focused on cancer research. There are 28 users with 42 peer reviewed grants who will use both the existing 7T and proposed 9.4/20 cm systems. The 4.7T/40 magnet is no longer operational and is beyond repair (please see letter from Bruker). The projects that have previously, and will continue to use the Small Animal MRI Core, focus on a range of oncologic problems, including developing and optimizing tumor models, predicting tumor response, immunology, and developing methods of monitoring tumor and drug metabolism to enhance therapeutic outcomes. The projects are highly translational, particularly the imaging aspects, based on the relatively widespread clinical availability of 3T MRI systems, and the growing (although still limited) availability of human magnets at higher field strengths. The long range goal of these collectively diverse preclinical projects is the improvement of cancer care by enhancing responses without enhanced toxicity, either by improving therapies or by development of early markers of response (or resistance) to avoid side effects and futile prolongation from ineffective treatments. The design and methods of these diverse projects share common principles to maximize the data obtained from the proposed system. Our goals include 1) continuing ?high-throughput?, high spatial resolution animal imaging needed by numerous investigators to evaluate new drugs and develop newer, more valid tumor models, 2) focusing more challenging experiments, particularly metabolic measurements and technically demanding imaging studies, on the proposed 9.4T magnet, 3) performing appropriate phantom and preliminary experiments to determine which NIH supported users' experiments will meaningfully benefit by use of the 9.4T magnet, 4) using statistically valid experimental groups, 5) integrating our new PET insert into the MR studies for truly simultaneous MR and PET; and 6) providing support to our users in experimental design, construction of appropriate hardware, and if necessary, performance of experiments to ensure that they are performed in an optimized manner. Relevance: The applications that will be supported on the proposed 9.4T instrument address a wide range of oncology problems. They include a focus on a wide spectrum of tumors (brain, prostate, breast, sarcomas, lung, colon cancers), addressing a variety of clinically relevant physiological problems in oncology (hypoxia, blood flow, drug delivery, the need for better tumor model systems, improvements in imaging, metabolism, immunology etc). The approaches to addressing these problems are quite varied but share the goal of translation from preclinical to the clinical realm.